1. Field of the Invention
The present invention relates to a wireless communication apparatus, a program, a wireless communication method and a wireless communication system.
2. Description of the Related Art
A wireless communication system based on the IEEE (Institute of Electrical and Electronic Engineers) 802.11 standards has been widespread. A wireless communication apparatus which constitutes such a wireless communication system is more advantageous than a wired communication system in that it has a high degree of flexibility such as portability. Further, an application which is used in each wireless communication apparatus becomes various, and a transmission speed which is demanded for a wireless communication system increases accordingly.
For example, according to “IEEE 802.11n” (prepared by the 802.11 Working Group of the 802 Committee, 2007), a plurality of MPDU (Mac Protocol Data Unit), which is a unit of transmission data in a MAC (Media Access Control) layer, are grouped into one MAC frame (which is referred to hereinafter as A-MPDU (Aggregate MPDU)). When an apparatus at the transmitting end transmits the A-MPDU packet, an apparatus at the receiving end transmits BA (Block ACK) as a reception confirmation signal indicating how many units of A-MPDU packet are received. If the apparatus at the transmitting end does not normally receive BA, it may transmit BAR (BA Request) for requesting the apparatus at the receiving end to retransmit BA.
If the apparatus at the transmitting end does not normally receive BA during a specified period where BA is expected to be received, the apparatus may perform any one of the following processing:    (1) Retransmitting an A-MPDU packet;    (2) Transmitting BAR; or    (3) Transmitting a new A-MPDU packet.